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During storage, irreversible changes occur in eggs, resulting in a decline in their quality, predominantly affecting the albumen. Ovomucoid, a major protein found in egg white, belongs to the Kazal-type serine proteinase inhibitors and serves to protect the embryo from microorganisms. Notably, in chicken eggs, it is a significant allergen. There is a possibility that its polymorphism also influences the quality and stability of table eggs. Hence, this study aimed to evaluate the potential effect of polymorphism in the ovomucoid gene and protein on quality changes during the storage of eggs derived from 2 strains of Japanese quail, encompassing various utility types. Eggs from selected females of laying and meat-type breeds were stored for 14 wk, with egg quality traits assessed 10 times during this duration. DNA was isolated from each female, and sequencing was conducted on all exons of the ovomucoid gene. In total, 5 SNPs were identified in exons and adjacent intronic sequences, with SNP1 (13:12355585), SNP4 (13:12356594), and SNP5 (13:12358538) leading to amino acid substitutions in the ovomucoid protein. Notably, all SNPs except SNP5 were identified in the ovomucoid gene of Japanese quail for the first time. The results demonstrated that in the F33 strain, SNP1, SNP3, and SNP4 exhibited significant associations with egg weight, whereas in the S22 strain, SNP5 significantly affected yolk color and various eggshell quality traits, including eggshell weight, eggshell thickness, and breaking strength, throughout the storage period. Furthermore, a haplotype block containing 2 SNPs (3 and 4) was identified, exhibiting 2 distinct haplotypes that significantly affected egg weight, eggshell weight, and breaking strength at various storage time points during egg quality analyses. These findings provide novel insights into the genetic basis of egg quality during storage and have the potential to be integrated into breeding programs for these strains., Competing Interests: DISCLOSURES The authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

As an anti-myogenic factor, the myostatin (MSTN) gene was mainly considered as a genetic marker to improve meat production. Moreover, an additional effect of the MSTN mutation on reducing fat deposition in various farm animals suggested a potential application of the MSTN gene on regulating fat deposition in poultry species. Although increase in muscle mass resulted from muscle hyperplasia in the MSTN mutant quail, cellular mechanism behind the decrease in fat deposition was not investigated in the quail model. In the current study, to investigate sexual dimorphic association between fat deposition and Mstn mutation in quail, leg and abdominal fat pads from 4-month-old male and female quail were histologically analyzed. Interestingly, abdominal and leg fat pad weights were significantly decreased by the MSTN mutation only in female quail, but not in male quail, showing sexual dimorphism in regulating fat deposition by the MSTN mutation in quail. Histological analysis also revealed that fat cell sizes of leg and abdominal fats were significantly reduced only in female groups aligning with the decreased fat pad weights. Sexual dimorphic effect of the MSTN mutation on fat cell hypotrophy and reduced fat pad weights in quail provided an important scientific finding to be considered on the usage of the MSTN gene as a genetic marker to reduce fat deposition in poultry species., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

During the storage irreversible changes occur in eggs that result in a deterioration of their quality. The most significant changes affect the albumen. One of the major proteins of albumen present in egg white is lysozyme, which protects the embryo from microorganisms. This enzyme also contributes to the qualitative characteristics of albumen. It is possible that its polymorphism also affects the quality and stability of the obtained raw material that is, table eggs. Therefore, the aim of this study was to assess the potential effect of polymorphism in the lysozyme gene and protein on the quality changes during the storage of eggs derived from 2 genetic strains of Japanese quail belonging to various utility types. Eggs from selected females of laying and meat-type breeds were stored for 14 wk. During this period the egg quality traits were evaluated 10 times. DNA was isolated from each female and all exons of the lysozyme gene had been sequenced. In total, fourteen SNPs' and one 4-bp indel mutation were identified in exons and adjacent intronic sequences, among which SNP1 (1:32140723) resulted in a substitution of lysine with glutamine (Q21K). The results showed that SNP1 (strain S22), as well as the SNP2, SNP5, SNP7, SNP8, SNP10, SNP11, SNP12 and SNP13 were significantly associated with breaking strength during egg storage in both investigated Japanese quail strains. Furthermore, a 3 haplotype blocks containing nine SNPs (2, 5, 6, 7, 8, 10, 11, 12 and 13) were identified. These blocks displayed 8 distinct haplotypes that had significant association with breaking strength at all storage time points where egg quality analyses were performed. The study also revealed significant effects of breed and storage time on the egg quality traits. These results provide new insights into the genetic basis of egg quality during storage and could be incorporated into the breeding programs involving these strains., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The meat of the quail is one of the most delicious types, as it is rich in minerals and vitamins, especially vitamin K, which is useful in treating nervous diseases. In the present investigation, based on their live body weight, 270 genetically-enhanced white quail chicks of mixed sex were randomly assigned to 3 groups, each with 90 chicks. The first group's birds were slaughtered at 28 d of age. The birds in the second group were slaughtered at 31 d, and the birds in the third group were slaughtered at 34 d. Results showed no significant difference between the various groups in the overall mortality rate index at the end of each fattening stage (P > 0.05). There were substantial variations (P ≤ 0.05) in the average live weight index between the first and both groups at each group's marketing age. With increasing marketing age, body weight increases. Quail chicks raised for 34 d received the lowest EPEF (28.90 points), followed by those raised for 31 d and 28 d, which received 33.37 and 37.32 points, respectively. The economic feasibility of the 3 groups, no significant differences in the profit index were observed at the age of 28 d. Compared to the marketing age of the other 2 groups, it was noted that the profit index decreased as the birds advanced in age. Delaying marketing to 31 d leads to a decrease in profit by 5.7%, and delaying marketing to 34 d reduces the profit index to 26.36% compared to marketing at 28 d. For blood hematology parameters, a significant increase in the studied indicators with the age of the birds was observed through the study of blood indicators. Still, it did not reach the significance level. It could be concluded that 28 d is the ideal marketing age for the enhanced white quails, as it yielded the highest economic return and the best performance., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Quail, as an advantageous avian model organism due to its compact size and short reproductive cycle, holds substantial potential for enhancing our understanding of skeletal muscle development. The quantity of skeletal muscle represents a vital economic trait in poultry production. Unraveling the molecular mechanisms governing quail skeletal muscle development is of paramount importance for optimizing meat and egg yield through selective breeding programs. However, a comprehensive characterization of the regulatory dynamics and molecular control underpinning quail skeletal muscle development remains elusive. In this study, through the application of HE staining on quail leg muscle sections, coupled with preceding fluorescence quantification PCR of markers indicative of skeletal muscle differentiation, we have delineated embryonic day 9 (E9) and embryonic day 14 (E14) as the start and ending points, respectively, of quail skeletal muscle differentiation. Then, we employed whole transcriptome sequencing to investigate the temporal expression profiles of leg muscles in quail embryos at the initiation of differentiation (E9) and upon completion of differentiation (E14). Our analysis revealed the expression patterns of 12,012 genes, 625 lncRNAs, 14,457 circRNAs, and 969 miRNAs in quail skeletal muscle samples. Differential expression analysis between the E14 and E9 groups uncovered 3,479 differentially expressed mRNAs, 124 lncRNAs, 292 circRNAs, and 154 miRNAs. Furthermore, enrichment analysis highlighted the heightened activity of signaling pathways related to skeletal muscle metabolism and intermuscular fat formation, such as the ECM-receptor interaction, focal adhesion, and PPAR signaling pathway during E14 skeletal muscle development. Conversely, the E9 stage exhibited a prevalence of pathways associated with myoblast proliferation, exemplified by cell cycle processes. Additionally, we constructed regulatory networks encompassing lncRNA‒mRNA, miRNA‒mRNA, lncRNA‒miRNA-mRNA, and circRNA-miRNA‒mRNA interactions, thus shedding light on their putative roles within quail skeletal muscle. Collectively, our findings illuminate the gene and non-coding RNA expression characteristics during quail skeletal muscle development, serving as a foundation for future investigations into the regulatory mechanisms governing non-coding RNA and quail skeletal muscle development in poultry production., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to perform a genome-wide association study (GWAS) based on Bayes A and Bayes B statistical methods to identify genomic loci and candidate genes associated with body weight gain, feed intake, and feed conversion ratio in Japanese quail. For this purpose, genomic data obtained from Illumina iSelect 4K quail SNP chip were utilized. After implementing various quality control steps, genotype data from a total of 875 birds for 2,015 SNP markers were used for subsequent analyses. The Bayesian analyses were performed using hibayes package in R (version 4.3.1) and Gibbs sampling algorithm. The results of the analyses showed that Bayes A accounted for 11.43, 11.65, and 11.39% of the phenotypic variance for body weight gain, feed intake, and feed conversion ratio, respectively, while the variance explained by Bayes B was 7.02, 8.61, and 6.48%, respectively. Therefore, in the current study, results obtained from Bayes A were used for further analyses. In order to perform the gene enrichment analysis and to identify the functional pathways and classes of genes that are over-represented in a large set of genes associated with each trait, all markers that accounted for more than 0.1% of the phenotypic variance for each trait were used. The results of this analysis revealed a total of 23, 38, and 14 SNP markers associated with body weight gain, feed intake, and feed conversion ratio in Japanese quail, respectively. The results of the gene enrichment analysis led to the identification of biological pathways (and candidate genes) related to lipid phosphorylation (TTC7A gene) and cell junction (FGFR4 and FLRT2 genes) associated with body weight gain, calcium signaling pathway (ADCY2 and CAMK1D genes) associated with feed intake, and glycerolipid metabolic process (LIPC gene), lipid metabolic process (ADGRF5 and ESR1 genes), and glutathione transferase (GSTK1 gene) associated with feed conversion ratio. Overall, the findings of this study can provide valuable insights into the genetic architecture of growth and feed consumption traits in Japanese quail., (Copyright © 2023. Published by Elsevier Inc.)

In the modern layer industry, improvement of bone quality is one of the prior tasks to solve from economic and welfare standpoints. In addition to nutritional and environmental factors, genetic factors have been considered major factors regulating bone quality in layers but are yet to be fully investigated due to limitations on available animal models. Initially, the myostatin (MSTN) gene was genetically edited in quail to investigate the effect of MSTN mutation on economic traits in meat producing poultry species. In the current study, the function of the MSTN gene on regulation of bone quality in layers was investigated using MSTN mutant female quail as an animal model. Tibia bones were collected from wild-type (WT) and MSTN mutant female quail at 5 wk old and 4 mo old, representing prelaying and actively laying stages, respectively. Left tibia bones were analyzed by microcomputed tomography scanning to evaluate the architectural characteristics, while bone breaking strength (BBS) was measured using right tibia bones. At 5 wk of age, MSTN mutant female quail showed higher BBS and values on parameters related to bone quality such as bone mineral contents (BMC), bone mineral density (BMD), bone volume (BV), and/or trabecular bone thickness in whole diaphysis, whole metaphysis, and metaphyseal trabecular bone, compared to WT female quail. Although BBS and BMD became similar between the 2 groups at 4 mo of age, higher TV and TS in whole metaphysis and higher BMC and TV in whole diaphysis of MSTN mutant group compared to those of WT group suggested that the improved tibia bone quality by MSTN mutation before sexual maturation lasted to a certain degree even after sexual maturation. The use of the MSTN mutant female model provided new insights into genetic regulation on female quail bone quality depending on physiological changes., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

This study aimed to identify polymorphisms of gonadotropin-releasing hormone (GnRH) gene and their association with growth traits in quail by PCR and direct sequencing. Genomic DNA was extracted from quail blood samples of 36 from Savimalt (SV) and 49 from French Giant (FG). Growth traits were measured and used for candidate gene analysis, as body weight (BW), shank length (SL), chest width (CW), chest depth (CD), breastbone length (BBL), body length (BL), and shank circumference (SC). The results showed that a total of 20 SNPs were detected in GnRH gene, whereas 8 SNPs were significantly associated with growth traits (P < 0.05). The T215C, G279A, C458T, A520G, and C547G were significantly associated with SL at 3 wk of age in the FG strain, whereas A583T was significantly related to BBL and BL, and C591T was significantly related to SL, BBL, and BL, whereas A592G was significantly correlated with SL, CW, CD, BBL, and BL (P < 0.05). The 8 SNPs were significantly related to CW, CD, and BBL at 3 wk of age in the SV strain, whereas A583T, C591T, and A592G were significantly associated with BW (P < 0.05). The G279A showed significant correlations with SL at 5 wk of age in FG, whereas A583T showed significant associations with SC in FG, and C591T was significantly associated with BW and SC in FG, whereas A592T was significantly related to BW, SL, and CD in FG (P < 0.05). The T215C, G279A, C458T, A520G, and C547G were significantly correlated with BW, CW, BBL, and BL at 5 wk of age in SV, whereas A583T, C591T, and A592G were significantly related to BW, SL, CW, BBL, and BL (P < 0.05). Haplotypes based on 8 SNPs showed significant correlation with BW, SL, CW, CD, BBL, BL, and SC in FG (P < 0.05). In conclusion, the GnRH gene could be used as a molecular genetic marker to provide theoretical foundation to improve growth traits in quail., (Copyright © 2023. Published by Elsevier Inc.)

Japanese quail is a low-fat, meat-bird species exhibiting high disease resistance. Cathelicidins (CATHs) are host defense peptides conserved across numerous vertebrate species that play an important role in innate immunity. The activity of host defense peptides can be affected by amino acid substitutions. However, no polymorphisms in avian CATH genes have been reported to date. The aim of this study was to clarify the polymorphisms in CATHs in Japanese quail. DNA for genomic analyses was extracted from the peripheral blood of 99 randomly selected quail from 6 inbred lines. A total of 6, 4, 6, and 4 CjCATH1, -2, -3, and -B1 alleles were identified, respectively. Nine haplotypes, including 4 strain-specific haplotypes, were identified by combining alleles at the CjCATH1, -2, -3, and -B1 loci. In addition, 2 and 1 amino acid substitutions (I145F, Q148H, and P245H) predicted by PROVEAN and PolyPhen-2 to have deleterious effects were detected in CjCATH2 and -B1, respectively. Synthetic CjCATH2 and -B1 peptides exhibited greater antibacterial activity against Escherichia coli than chicken CATH2 and -B1, respectively. Furthermore, the CjCATHB1∗04 peptide exhibited less potent antimicrobial activity than other CjCATHB1 peptides examined. This is the first report of amino acid substitutions accompanied by changes in antibacterial activity in avian CATHs. These findings could be employed as indicators of improvements in innate immune response in poultry., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Myostatin (MSTN) negatively regulates in muscle growth and development. Among alternative splicing isoforms of avian MSTN, MSTN-A has antimyogenic activities and MSTN-B functions as a promyogenic factor. In this study, different lines of Japanese quail were used: a random bred control (RBC) and a heavy weight (HW) quail line with muscle hypertrophy. The objectives of the current study are to compare temporal expression of the MSTN isoforms in pectoralis major muscle (PM) between 2 quail lines and to relate MSTN expression with temporal changes in muscle growth and total amounts of DNA in PM. Gains of body weight (BW) and PM weight were greater until posthatch day (D) 28 (P < 0.001), and the fold increases in total DNA contents of PM were greater in the HW line compared with the RBC line during D7 to D28 (P < 0.05). PCR analysis showed that MSTN-A expression was greater at 14 D (E14) of embryonic age (P < 0.01), D7 (P = 0.052), and D14 (P < 0.01) in the RBC line compared with the HW line. At D28 and D75, expression of MSTN-A was greater in the HW line compared with the RBC line (P < 0.05). MSTN-B expression was barely detectable from E14 to D14 and measurable from D28 to D75 in the muscle of both lines. Ratios of the MSTN-B/-A form ranging from 0.15 to 0.29 indicate a minor expression of the B form. Taken together, the lesser expression levels of MSTN-A at E14, D7, and D14 are associated with the fast growth of PM, and greater MSTN-A expression at D28 and D75 are associated with a slowdown of PM growth in the HW line. These data indicate a negative association of MSTN expression with PM growth and provide a scientific basis for potential usage of MSTN expression as a selection marker for greater muscle growth in poultry., (Copyright © 2020. Published by Elsevier Inc.)

The main objective of this study was to perform quantitative genetic analyses of tibia and foot ash traits, which might serve as proxy traits to improve phosphorus utilization (PU) in a breeding program. Additionally, data for ash concentration in tibia and foot were compared with data for total amount of ash. Heritabilities for bone ash traits and genetic and phenotypic correlations between bone ash traits and PU were estimated. A total of 887 F2 birds, established from 2 Japanese quail lines divergently selected on social reinstatement behavior, were provided a P deficient diet. In a metabolic study, feed consumption was measured and total excreta collected for each bird separately. Afterwards, birds were euthanized, the bones obtained and incinerated. Bone ash data showed a heritability of 0.230 (amount of tibia ash) to 0.342 (amount of foot ash), which was higher than estimated for PU, P retention, calcium utilization (0.120-0.174), and performance traits (0.088-0.114). The strongest genetic and phenotypic correlations between PU and bone ash traits were detected for the amount of foot ash with 0.549 and 0.527, respectively. Genetic and phenotypic correlations were stronger between PU and ash amount than between PU and ash percentage, irrespective of bone. Therefore, ash amount was considered a better trait than ash percentage to reflect PU. Strong genetic and phenotypic correlations were detected between the amount of foot and tibia ash (0.887 and 0.901, respectively). Phenotypic and genetic correlations between ash amount and PU or calcium utilization were almost identical, irrespective of bone. Foot ash is as suitable as tibia ash, but easier to determine. Bone ash data, especially the amount of foot ash, seem to be suitable indirect selection criteria for P efficiency breeding., (© The Author(s) 2019. Published by Oxford University Press on behalf of Poultry Science Association.)

Blue-breasted quail has been recognized as a potential model animal. The aim of this study is to investigate the low-temperature-induced embryonic diapause in blue-breasted quail. To this end, the early embryonic staging in blue-breasted quail was briefly described and various incubation temperatures were tested. While the embryonic diapause in early blue-breasted quail embryos can be induced when the eggs were stored at 21°C, a lower temperature such as 16°C yielded a significantly better hatchability (P = 0.0231). Additionally, prolonged storage duration from 3, 7 to 14 d significantly reduced the hatchability (P < 0.0001). Visual examination on the unhatched eggs revealed that reduced hatchability in prolonged storage was significantly correlated with embryonic mortality during the first half of incubation period (R2 = 0.9999, P = 0.0055). High-throughput RNA sequencing with de novo assembly showed that a gene network cluster consisted of ND4, ND5, ND6, and COX3, which are components of mitochondrial respiratory complexes, was down-regulated in the cold-stored embryos, while a stress-responsive gene network cluster consisted of JUN, ATF3, and DUSP1 was up-regulated. Accordingly, cell death in the blastoderm was significantly increased as the storage duration prolonged from 3 to 10 d. Taken together, our study provided basic information on the temperature-induced embryonic diapause in blue-breasted quail. Furthermore, transcriptomic analysis sheds light for the molecular basis on how blastoderm cells respond to the prolonged cold-stress and stay diapause., (© 2019 Poultry Science Association Inc.)

This study aimed to compare different nonlinear functions to describe the growth curve of European quails and to estimate growth curve parameters, (co)variance components, and genetic and systematic effects that affected the curve using a hierarchical Bayesian model that allows joint estimation. Three different models were fitted in the first stage (Gompertz, Logístic, and von Bertalanffy). The analyzed data set had 45,965 records of 6,838 meat quails selected for higher body weight at 42 d of age for 15 successive generations, weighed at birth, 7, 14, 21, 28, 35, and 42 d of age. Comparisons of the overall goodness of fit were based on deviance information criterion (DIC) and mean square error. Gelfand's check function compared the models at different points of the growth curve. In the second stage, the systematic (sex and generation) and genetic effects were considered in an animal model. Random samples of the a posteriori distributions were obtained by Metropolis-Hastings and Gibbs sampling algorithms. The Gompertz function presented lower DIC and better adjustment at different ages and was defined as the best fit. The heritabilities of A, b, and k parameters were moderate (0.32, 0.29, and 0.18, respectively). The genetics correlations were A and b (0.25), A and k (-0.50), and b and k (0.03). The samples of the posterior marginal distributions for the differences between the estimates of the parameters of the Gompertz model, for generation, A, b, k, age at inflexion point (APOI), and weight at inflexion point (WPOI) showed differences in relation to sex, the females are heavier, A, WPOI, and APOI for females were also higher. In conclusion, 15 generations of selection and changes in the environmental conditions altered the growth curve, leaving the quails heavier and with greater WPOI and APOI, decreased growth rate, and increased the birth weight. The curve parameters could be used in a selection index, despite the difficulty in selecting quails with higher rate of growth and adult body weight., (© 2018 Poultry Science Association Inc.)

A major part of the growth performance in birds is the result of the combined effects of genes, including the general and specific combining ability that requires the design of an optimal mating system. The aim of this study was to fit the best model for each body weight trait from hatch to 45 days and the estimation of the variance components and the genetic parameters for the body weight traits of a crossbred population. This crossbred population was created by 4 strains of Japanese quail, including the Italian Speckled (A), Tuxedo (B), Pharaoh (C), Texas A&M (D), and the body weights of the different combinations were analyzed by 24 models including the direct genetic effect, the non-additive genetic effects including dominance and epistatic effects, the maternal permanent environmental and maternal genetic effects. The selection of the best fit model of each trait was performed based on the deviance information criteria. The variance components were estimated using a single-trait animal model analyzed with Gibbs sampling. At the early stage of bird growth, maternal genetic and maternal permanent environmental effects had a considerable contribution to the best model, but the contribution of these effects reduced with an increase in the bird's age and the additive variance contribution increased. Adding non-additive genetic effects (dominance and epistasis) to the models significantly reduced the variance of the error and the additive genetic variance estimated with high accuracy. The estimated heritability of body weight traits for the body weights of hatch, 5, 10, 15, 20, 25, 30, 35, 40, and 45 d were 0.316, 0.170, 0.251, 0.153, 0.132, 0.164, 0.290, 0.425, 0.476, and 0.362, respectively. The ratio of maternal genetic and maternal permanent environmental was considerable especially on early age body weight but the ratio of dominance and epistatic variances on each of the body weight traits was less than 4.5% of the total variance, but led to a more accurate estimates of the direct additive genetic.

The aim of the present study was to estimate heritabilities and evaluate the existence of genotype-environment interactions for growth curve parameters in quail fed diets containing different threonine:lysine ratios. A total of 4,441 body weight information from two genetic quail groups (LF1 and LF2) fed diets containing 0.66%, 0.71%, 0.76%, 0.81%, and 0.86% threonine:lysine ratios from hatching to 21 d of age were evaluated. From 22 to 35 d of age, quail received a single diet. The Gompertz model was used to estimate growth curve parameters. Genetic analyses were performed using random regression models, by Legendre polynomials of the second kind, considering homogeneity of residual variances. The following characteristics were evaluated: asymptotic weight, asymptotic growth rate, and inflection point. Increases in threonine:lysine ratios promoted higher heritability estimates for these variables in the LF1 genetic group compared to LF2, which indicates that the additive genetic variation was modified due to the environmental variation influenced by the evaluated amino acid ratios, with differences between both genetic groups. Thus, it is recommended that quail be selected in the 0.86% ratio in genetic group LF1 and 0.66% in genetic group LF2, where greater heritabilities were observed. Dispersion of individual breeding values along the environmental gradient was observed for all evaluated characteristics, in both genetic groups, suggesting the existence of genotype-environment interactions for these variables. The evaluated amino acid ratios should be considered in quail breeding programs, since breeding value predictions for a determined threonine:lysine ratio are not valid for other ratios.

The major objective of this study was to assess the expression of mitochondrial hormone receptors for progesterone (PR), estrogen (ER), glucocorticoid (GR), thyroid (TR), and insulin (IR) in avian muscle cells (quail muscle 7, QM7) and in breast muscle of quail and broilers. Visualization of receptor location in QM7 cells was accomplished by immunofluorescence. QM7 cells were stained with Mito Tracker Deep Red CMX, fixed in methanol, immune stained with anti-PR, -GR, -TR, -IR, and -ER primary antibodies overnight at 4°C, and visualized with Alexa Fluor 488-conjugated secondary antibody. After staining the nucleus with 4',6-diamidino-2-phenylindole, images were obtained by immunofluorescence microscopy. Merged images revealed the presence of all 5 hormone receptors on mitochondria in QM7 cells. Western blot analysis identified; (a) the β-isoform of the PR, (b) the α-isoform of GR, (c) the α-receptor of TR, (d) the β-subunit of IR, and (e) the α-isoform of the ER on mitochondria isolated from broiler breast muscle. Similar results were obtained in quail breast muscle mitochondria with the exception that the α-isoform of the GR was not detected. To our knowledge, this is the first report of hormone receptors (PR, TR, GR, IR, and ER) on mitochondria in avian cells. We hypothesize that these receptors could play important roles in regulating mitochondrial function in avian muscle cells.

The objective of the current study was to identify QTL associated with body weight, growth rate, egg quality traits, concentration of selected blood plasma, and yolk lipids as well as concentration of selected macro- and microelements, color, pH, basic chemical composition, and drip loss of breast muscle of Japanese quail (Coturnix japonica). Twenty-two meat-type males (line F33) were crossed with twenty-two laying-type females (line S22) to produce a generation of F1 hybrids. The F2 generation was created by mating 44 randomly chosen F1 hybrids, which were full siblings. The birds were individually weighed from the first to eighth week of age. At the age of 19 wk, 2 to 4 eggs were individually collected from each female and an analysis of the egg quality traits was performed. At slaughter, blood and breast muscles were collected from 324 individuals of the resource population. The basic chemical composition, concentration of chosen macro- and microelements, color, pH, and drip loss were determined in the muscle samples. The concentration of chosen lipids was determined in egg yolk and blood plasma. In total, 30 microsatellite markers located on chromosome 1 and 2 were genotyped. QTL mapping including additive and dominance genetic effects revealed 6 loci on chromosome 1 of the Japanese quail affecting the egg number, egg production rate, egg weight, specific gravity, egg shell weight, concentration of Na in breast muscle. In turn, there were 9 loci on chromosome 2 affecting the body weight in the first, fourth, and sixth week of age, growth rate in the second and seventh week of age, specific gravity, concentration of K and Cu in breast muscle, and the levels of triacylglycerols in blood plasma. In this study, QTL with a potential effect on the Na, K, and Cu content in breast muscles in poultry and on specific gravity in the Japanese quail were mapped for the first time.

The main objectives of this study were to detect the most appropriate random regression model (RRM) to fit the data of monthly egg production in 2 lines (selected and control) of Japanese quail and to test the consistency of different criteria of model choice. Data from 1,200 female Japanese quails for the first 5 months of egg production from 4 consecutive generations of an egg line selected for egg production in the first month (EP1) was analyzed. Eight RRMs with different orders of Legendre polynomials were compared to determine the proper model for analysis. All criteria of model choice suggested that the adequate model included the second-order Legendre polynomials for fixed effects, and the third-order for additive genetic effects and permanent environmental effects. Predictive ability of the best model was the highest among all models (ρ = 0.987). According to the best model fitted to the data, estimates of heritability were relatively low to moderate (0.10 to 0.17) showed a descending pattern from the first to the fifth month of production. A similar pattern was observed for permanent environmental effects with greater estimates in the first (0.36) and second (0.23) months of production than heritability estimates. Genetic correlations between separate production periods were higher (0.18 to 0.93) than their phenotypic counterparts (0.15 to 0.87). The superiority of the selected line over the control was observed through significant (P < 0.05) linear contrast estimates. Significant (P < 0.05) estimates of covariate effect (age at sexual maturity) showed a decreased pattern with greater impact on egg production in earlier ages (first and second months) than later ones. A methodology based on random regression animal models can be recommended for genetic evaluation of egg production in Japanese quail., (© 2017 Poultry Science Association Inc.)

An experiment was conducted to evaluate egg quality and ultrastuctural measurements of eggshell using a Scanning Electron Microscope (SEM) in 2 lines (selected and control) of Japanese quail. A selection program was applied over 22 consecutive generations for higher egg production and lower broken egg percentage. The results revealed that the females of the selected line produced significantly (P < 0.01) higher egg mass compared to that of the control line. Also, the selection procedure significantly improved feed conversion ratio. The eggshells of the selected line had a higher breaking strength compared to those of the control line, although there was no difference between them in shell thickness. Significantly higher wet (P < 0.01) and dry (P < 0.05) eggshell percentages were found in the selected line. In general, the eggshells of the selected line had a lower total score (good) of ultrastructural evaluation compared to the control line. According to scanning electron microscope data, the incidence of certain structural variants was more common in eggshells of the control line suggesting poor shell strength. The incidence of alignment was more prevalent in control eggshells compared to selected ones, suggesting lower resistance to breakage. Late fusion and large interstitial spaces of the palisade layer indicating decreased resistance to fracture were observed in control eggshells. It could be concluded that the improvement eggshell quality may be caused by the long-term selection for lower cracked and broken egg rates from generation to generation., (© 2016 Poultry Science Association Inc.)

This study was conducted to determine the genetic parameters of internal and external quality traits of Japanese quail eggs. Two statistical models were used in the calculation of genetic parameters and variance components. While 286 eggs were used based on model 1, 1,524 eggs were used based on model 2. Genetic parameters of the first eggs were calculated with direct genetic effect included in the analysis as random factors by using model 1. Model 2 was used for all eggs (5 to 6 eggs from each hen for six rearing groups). As different from model 1, their permanent environmental effects were also included in the model 2. Heritability of egg weight, egg length, egg width, shape index, shell weight, shell thickness, and shell ratio among the external quality traits of the eggs was respectively found to be 0.44, 0.53, 0.51, 0.70, 0.19, 0.16, and 0.05, respectively, according to model 1. These values were found to be 0.46, 0.40, 0.74, 0.48, 0.60, 0.28, and 0.21, respectively, according to model 2. Yolk weight, yolk diameter, yolk height, yolk index, yolk ratio, albumen weight, albumen height, albumen ratio, and Haugh unit values among the internal quality traits of the egg were found to be 0.22, 0.32, 0.02, 0.16, 0.19, 0.34, 0.19, 0.17, and 0.17, respectively, according to model 1. These internal quality traits were found to be 0.27, 0.18, 0.38, 0.06, 0.20, 0.41, 0.15, 0.15, and 0.12, respectively, according to model 2. Consequently, in this study, strong genetic correlations were detected between albumen height and Haugh unit, and also between albumen height and albumen weight. Additionally, a high and positive correlation was observed between some yolk traits (yolk weight and diameter) and albumen traits (weight and height). All these genetic correlations can be used to improve egg quality with a selection according to albumen weight., (© 2016 Poultry Science Association Inc.)

Phosphorus utilization (PU) has received considerable attention in poultry nutrition. However, reliable estimates of genetic parameters for PU and related traits have largely not been reported until now; however, these are needed to assess whether selection for an improved PU would result in selection response. A large Japanese quail F2 cross was generated and 888 F2 individuals were phenotyped for PU, bodyweight gain (BWG), and feed per gain (F:G). Because it can reasonably be assumed that the interrelationships between these traits are complex, structural equation models were used. The structural coefficient λij describes the rate of change of trait I with respect to trait j for a model with a recursive effect of trait j on trait i Three recursive structural coefficients (λF:G,PU,λBWG,PU,λBWG,F:G) were selected a priori based on biological knowledge. The model was fitted using ASReml software. Standard errors of estimated variance components and genetic parameters were approximated using the delta method. The heritability of PU, F:G, and BWG were 0.136, 0.118, and 0.092. The structural coefficient[Formula: see text]indicates that an increase in PU leads to reduced and thus improved F:G. The estimate[Formula: see text]indicates that improved F:G leads to an increase in BWG. The overall effect of PU on BWG was[Formula: see text]i.e. an increase in PU of 1% leads to an increase of BWG of 0.374 g in the data collection period, which spanned five days. The phenotypic and genetic correlations were negative between PU and F:G as well as between BWG and F:G and were positive between PU and BWG. These correlations are driven by direct genetic effects (pleiotropic genes or genes being in linkage disequilibrium) as well as by indirect genetic effects (genes affecting trait j affected indirectly trait i). The application of structural equation models contributed to our understanding of the complex biological relationship between PU, F:G, and BWG in quails. PU shows a heritability that is sufficient to achieve a selection response when breeding for this very-hard-to-measure trait., (© 2016 Poultry Science Association Inc.)

The objective of the current study was to evaluate a multi-trait selection program based on aggregated breeding values using an animal model Best Linear Unbiased Prediction (BLUP) in Japanese quail. The estimated genetic gain was compared by both mixed model and least squares methods. Data of 1,682 female Japanese quails were collected through four consecutive generations to estimate genetic gain, depending on aggregated breeding values, for age at first egg (AFE), body weight at sexual maturity (BWSM), and days needed to produce the first ten eggs (DN10). Estimates of cumulative selection response were favorable for all the studied traits and significant for AFE (-3.03) and BWSM(10.38), but not significant for DN10(-0.15). Estimates of direct heritability were moderate for AFE (0.21) and BWSM(0.25) but low for DN10(0.08), while estimates of maternal heritability were moderate for AFE (0.19) but low for BWSM(0.04) and DN10(0.01). High (0.45 to 0.56) genetic and low (-0.01 to -0.18) phenotypic correlations were observed among the studied traits. Negative (-0.23 to -0.95) correlations between additive genetic and maternal genetic effects were observed for all traits. Genetic trends were -0.76 (P=0.031), 2.54 (P=0.037), and -0.06 (P=0.052) with calculated product-moment correlations between breeding values, estimated by BLUP and phenotypic selection methods, of 0.78 (P=0.002), 0.77 (P=0.004), and 0.61 (P=0.007) for AFE, BWSM, and DN10, respectively. Aggregated breeding value estimation based on animal model BLUP could be an effective method of constructing a selection program to achieve a favorable selection response in egg production traits in Japanese quail., (© 2016 Poultry Science Association Inc.)

The objective of this study was to compare the temporal expression of myosin heavy chain (MyHC) isoforms, Pax7, and myogenic regulatory factors (MRF) between heavy weight (HW) and random bred control (RBC) Japanese quail lines during muscle development to better understand the mechanisms leading to increased skeletal muscle mass in the HW quail line selected for a greater BW at 4 wk of age separated from RBC quail. Expression of neonatal MyHC isoform began at 3 and 7 d posthatch in RBC and HW quail lines, respectively. In the RBC quail line, adult MyHC isoform, as a marker for muscle maturation, was expressed at 28 d posthatch with sustained expression through 75 d posthatch, whereas this protein was detected only at 75 d posthatch in the HW quail line. Moreover, Pax7 expression continued from embryonic ages to 14 d posthatch in the HW quail line and to 7 d posthatch in the RBC quail line. These expression patterns of MyHC isoforms and Pax7 in the HW quail line were accompanied by delayed muscle maturation and prolonged growth compared with the RBC quail line. Temporal expressions of the primary MRF showed that higher expression levels of MyoD and Myf-5 were observed at 9 and 11 d embryo in the HW quail line compared with the RBC quail line (P < 0.05). The HW quail line exhibited approximately 2 times greater average levels of myogenin expression from 7 to 75 d posthatch (P < 0.05) than the RBC quail line. Prolonged upregulation of these primary and secondary MRF during muscle development is associated with delayed maturation and continued muscle growth, which consequently would permit muscle hypertrophic potentials in the HW quail line compared with the RBC quail line., (© 2014 Poultry Science Association Inc.)

The current research was conducted to compare growth, carcass traits, pH, intramuscular collagen (IMC) properties, and genetic bases of IMC and carcasses (breast-muscle weight) of different lines and generations of adult males and females of Japanese quail (Coturnix japonica). Forty-four quails (generation F0), 22 Pharaoh (F-33) meat-type males and 22 Standard (S-22) laying-type females, were crossed to produce the F1 hybrids generation. The F2 generation was created by mating one F1 male with one F1 female, full siblings. The birds, randomly chosen from F0 (22 males and 22 females), F1 (22 males and 22 females), and F2 (84 males and 152 females) were raised to 20 wk of age in collective cages. Quails were fed ad libitum commercial diets. At slaughter, all birds were individually weighed (after a fasting period of 12 h) and dressing yield (without giblets) was calculated. The carcasses were then dissected. Genomic DNA was extracted from all of the blood, and 30 microsatellite markers located on 2 quail chromosomes were genotyped. The F -: 33 quails had higher in vivo and postmortem performances and a higher abdominal fat percentage than those of the egg line. Meat from S -: 22 quails had a slower collagen maturation (hydroxylysylpyridinoline crosslink/collagen) and a higher ultimate pH. The F1 and F2 generations showed an evident sexual dimorphism, and an additional effect could be due to hybrid heterosis evident in F2. Meat from quails of F1 and F2 generations had a lower IMC amount with a higher degree of collagen maturation compared with parental lines. Two statistically significant QTL have been detected on quail chromosome 2 (CJA02): a QTL with an additive effect (0.50) for IMC in the marker bracket GUJ0037 and GUJ0093; a second QTL with additive (1.32) and dominant (1.91) effects for breast-muscle weight in the marker bracket GUJ0084 and GUJ0073. To our knowledge, this is the first report of a QTL associated with breast-muscle weight and IMC in quail and poultry species, respectively., (© Poultry Science Association Inc.)

This study estimated the genetic variance components of P utilization in Japanese quail. A parental generation was assembled from an unselected random-bred Japanese fattening quail line. Seven sires and 14 dams were randomly selected, and each sire was paired with 2 dams to produce full and half sibs. A total of 200 unsexed 1-d-old quail with known pedigree were wing-banded and raised during the first 4 d posthatch in groups in floor pens on wood shavings and fed a preexperimental diet that was adequate in all nutrients. Starting on d 5, quail were individually housed in metabolic compartments on P-free filter paper. This started a balance trial with 5 d of adaption and 5 d of total excreta collection. During this balance period, all quail were fed a low-P (3.9 g/kg of DM) corn-soybean meal-based diet with a Ca:P ratio of 1.6:1.0. Phosphorus and Ca utilization were determined individually using the difference in P or Ca intake and the total P or Ca excretion. The average P utilization was 72% and the average Ca utilization was 63%, each with very high variation. Heritabilities were estimated to be 0.09 (SE = 0.09) for P utilization and 0.09 (SE = 0.09) for Ca utilization. Heritabilities were close to the values reported in the literature for broilers and suggest that quail are suitable as a model animal. The SE of the heritability estimates were large. This implies that further studies with a larger sample size are needed to identify genetic and physiological mechanisms that influence P and Ca utilization in Japanese quail., (© Poultry Science Association Inc.)

Poultry are capable of laying unfertilized eggs in which embryonic development occurs; this phenomenon is called parthenogenesis. Through genetic selection, the incidence of parthenogenesis in virgin Chinese Painted Quail hens can be increased. However, it is unknown if selection for this trait affects hatchability of fertilized eggs. Therefore, the objective of this study was to determine if genetic selection for parthenogenesis in virgin Chinese Painted Quail affects hatchability of mated hens. At 4 wk of age, females were separated from males and individually caged. Daily, eggs were collected, labeled, and stored from 0 to 3 d at 20°C then incubated at 37.5°C. At d 10 of incubation, eggs from virgin hens were broken out to determine the incidence of parthenogenesis. After the incidence of parthenogenesis in virgin hens was determined, hens were selected for mating. Eggs from the parent stock and generations 1 through 7 that did not hatch were examined for stage of hatching failure and categorized as infertile or possible parthenogens as well as early, middle, and late embryonic mortality. For hatch of set and hatch of fertile eggs, generation 1 hatched the greatest percentage of eggs compared with the other generations. Also, as the generation of selection increased, there was a linear decline in the percentage of eggs hatched for both hatch of set and hatch of fertile eggs. Additionally, generation 2 had the highest percentage of infertile eggs. There was a linear increase as generation of selection increased for both the percentage of eggs exhibiting possible parthenogens and early embryonic mortality. Unlike early embryonic mortality, the parent generation had the greatest percentage of embryos die in both the middle and late stage of incubation. In conclusion, it appears that selecting Chinese Painted Quail for the parthenogenetic trait impairs hatchability when hens are mated.

The aim of this study was to evaluate the relationship between slaughter age and slaughter-carcass characteristics in 2 quail lines. With this aim, a Japanese quail flock subjected to mass selection to increase BW for 4 generations and a control flock that randomly mated for 4 generations were used. Birds of both lines were slaughtered at 4, 5, 6, 7, and 8 wk of age. Weights of carcass, breast, leg, wing, edible inner organs, and abdominal fat, and their percentages in BW were measured. Short-term mass selection for increased BW resulted in an increase for all slaughter and carcass traits, except edible inner organ percentage. Slaughter age had a significant effect on the studied traits, indicating that the BW and weight of carcass, carcass parts, abdominal fat, edible inner organs, and percentage of abdominal fat increased with increased slaughter age. Conversely, the carcass yield and percentages of carcass parts and edible inner organs were decreased with an increase in slaughter age. The present study showed that deterioration in carcass quality occurred with an increase in slaughter age. Furthermore, the differences between the carcass weights over the different ages ranged between 16.83 to 22.45% in favor of the selection line after a short-term mass selection.

The goal of selection studies in broilers is to obtain genetically superior chicks in terms of major economic traits, which are mainly growth rate, meat yield, and feed conversion ratio. Multiple selection schedules for growth and reproduction are used in selection programs within commercial broiler dam lines. Modern genetic improvement methods have not been applied in experimental quail lines. The current research was conducted to estimate heritabilities and genetic correlations for growth and reproduction traits in a Japanese quail flock. The Gompertz equation was used to determine growth curve parameters. The Gibbs sampling under a multi-trait animal model was applied to estimate the heritabilities and genetic correlations for these traits. A total of 948 quail were used with complete pedigree information to estimate the genetic parameters. Heritability estimates of BW, absolute and relative growth rates at 5 wk of age (AGR and RGR), β0 and β2 parameters, and age at point of inflection (IPT) of Gompertz growth curve, total egg number (EN) from the day of first lay to 24 wk of age were moderate to high, with values ranging from 0.25 to 0.40. A low heritability (0.07) for fertility (FR) and a strong genetic correlation (0.83) between FR and EN were estimated in our study. Body weight exhibited negative genetic correlation with EN, FR, RGR, and IPT. This genetic antagonism among the mentioned traits may be overcome using modern poultry breeding methods such as selection using multi-trait best linear unbiased prediction and crossbreeding.

One challenge faced by ethologists in poultry welfare is helping birds to form functionally successful groups over time through the expression of appropriate behaviors. Searching for phenotypic variability, we developed in Japanese quail a density-related permanence (DRP) test that enables us to classify young birds (while in groups) according to their individual permanence in boxes containing a high or low density of confined conspecifics (HD or LD, respectively). This study addressed the question of whether contrasting DRP quail behavior may reflect underlying differences in social responses. Birds were classified at 11 d of age in an apparatus consisting of 2 boxes interconnected by a central region delimited by sliding doors. Each box contained at its distal end either 12 or 3 conspecifics confined behind a glass (high or low density, respectively). The doors were closed 9 times every 1 h, and positioning of 36 experimental birds was registered. If birds were found in the box containing high density, low density, or in the central region, they received a 1, -1, or a 0 score, respectively. Birds with final summed scores of ≥3 or ≤-3 were categorized as HD or LD, respectively. Same category groups (HD or LD) were evaluated in their home box (undisturbed) and in a resident/intruder test when 38 d old. A higher proportion of LD than HD groups (5/6 vs. 1/6, respectively) showed at least one aggressive pecking event during a 1-h trial. The LD groups also showed a higher number of aggressive pecking events than HP groups. When an unfamiliar intruder (either HD or LD) was incorporated during 5 min in the HD or LD box, LD resident quail showed shorter latencies and a higher number of aggressive pecking events toward the intruder bird than their HD counterparts. The early individual permanence in the DRP test could be considered a consequence of a different adaptability strategy for group living. This novel test could be relevant for selection programs aiming to obtain birds better suited for rearing in high-density conditions.

The aim of this study was to investigate the DNA content and morphological characteristics of muscle fibers, and their relation to the growth performance in random bred control (RBC) and heavy weight (HW) Japanese quail lines. The 2 lines were of similar embryo size at 6 and 8 d of incubation; however, HW quail were significantly larger than their counterparts after 10 d of incubation (P < 0.05). The hatch weight of the HW quail line was approximately 1.3-fold higher than the RBC quail line (P < 0.001). After 15 d posthatch, the BW and pectoralis major muscle weight (PMW) exhibited remarkable differences between the 2 quail lines. The RBC line showed a faster rate of increase in PMW (2.7- vs. 2.1-fold) and total DNA mass (2.2- vs. 1.6-fold) between 0 and 4 d posthatch. The HW line exhibited a greater rate of the PMW (33.0- vs. 12.9-fold) and total DNA mass (10.3- vs. 4.0-fold) between 4 and 15 d posthatch than the RBC line. Moreover, the greatest increase in total DNA mass occurred between 0 and 8 d posthatch for the RBC line and 4 to 15 d posthatch for the HW line. These differences in the DNA content indicate a difference in the hypertrophic potential of muscle fibers between the 2 quail lines. The cross-sectional area of muscle fibers was 1.3-fold greater in the HW line compared with the RBC line at 8 d posthatch (158.5 vs. 97.11 μm(2), P < 0.001), and this difference increased with age (over 2.1-fold greater in the HW line). Thus, the most important time windows affecting ultimate body and muscle weights in the RBC and HW quail lines are between 0 to 8 d and 4 to 15 d posthatch, respectively. Rapid muscle growth rate and a greater muscle mass in the HW quail line may be partially due to the hypertrophic potential of muscle fibers, which is characterized by larger fiber size.

The aim of this study was to evaluate the genetic parameters of several breast meat quality traits and their genetic relationships with some slaughter traits [BW, breast yield (BRY), and abdominal fat yield (AFY)]. In total, 1,093 pedigreed quail were slaughtered at 35 d of age to measure BRY, AFY, and breast meat quality traits [ultimate pH (pHU), Commission Internationale d'Eclairage color parameters (L*, lightness; a*, redness; and b*, yellowness), thawing and cooking loss (TL and CL, respectively), and Warner-Bratzler shear value (WB)]. The average pHU, L*, a*, and b* were determined to be 5.94, 43.09, 19.24, and 7.74, respectively. In addition, a very high WB average (7.75 kg) indicated the firmness of breast meat. High heritabilities were estimated for BW, BRY, and AFY (0.51, 0.49, and 0.35). Genetic correlations of BW between BRY and AFY were found to be high (0.32 and 0.58). On the other hand, the moderate negative relationship between BRY and AFY (-0.24) implies that selection for breast yield should not increase abdominal fat. The pHU was found to be the most heritable trait (0.64), whereas the other meat quality traits showed heritabilities in the range of 0.39 to 0.48. Contrary to chickens, the genetic correlation between pHU and L* was low. The pHU exhibited a negative and high correlation with BW and AFY, whereas L* showed a positive but smaller relationship with these traits. Moreover, pHU exhibited high negative correlations (-0.43 and -0.62) with TL and WB, whereas L* showed a moderate relationship (0.24) with CL. This genetic study confirmed that the multi-trait selection could be used to improve meat quality traits. Further, the ultimate pH of breast meat is a relevant selection criterion due to its strong relationships with either water-holding capacity and texture or low abdominal fatness.

Japanese quail selected for divergent corticosterone response to restraint stress were evaluated for their susceptibility to heat stress and challenge with Escherichia coli. These quail lines are designated as high stress (HS), low stress (LS), and the random-bred control (CS) lines. Heat stress (35°C, 8 h/d) began at 24 d until the end of the study at 39 d. Birds were challenged with an aerosol spray containing 2 × 10(9) cfu of E. coli at 25 and 32 d. At 38 d, the surviving birds were necropsied and the intestinal tract was screened for both Salmonella and Campylobacter. Body weights of the CS birds were higher than both HS and LS at 17, 25, and 32 d. At 32 d, there was no difference in mortality between males and females and the CS line had higher mortality compared with the LS line with the HS line being intermediate. At 38 d, females of the CS line that were both heat stressed and challenged had a mortality incidence of 25%, which was significantly higher than male birds of the same line and treatment (5.3%). There was an increased incidence in Salmonella enterica serotype Agona isolation after heat stress, with the LS birds having less isolation than the HS birds. Mean corticosterone levels of male birds were not significantly affected by line, heat stress, or E. coli challenge; however, the LS line subjected to heat stress had one-third the level of the HS line, a difference identical to that seen in the original selection for response to restraint stress.

Current research was conducted to estimate heritability and genetic correlations for carcass composition and fat deposition in Japanese quail at 42 and 91 d of age. Studied traits were BW at 42 and 91 d of age (BW42, BW91), carcass weight and percentage, breast meat weight and percentage, thigh weight and percentage, abdominal fat weight and abdominal fat percentage (AFP), skin weight and skin percentage (SP) as a measure of subcutaneous fat, and the percentage of breast intramuscular fat (IFP). Genetic parameters were estimated by restricted maximum likelihood using ASREML software. The heritability estimates of BW and the weight of carcass traits were higher (from 0.45 for BW42 to 0.63 for breast meat weight) than the percentage of carcass traits (from 0.11 for thigh percentage to 0.19 for breast meat percentage). The heritability estimates for SP, AFP, and IFP as fat deposition tissues were 0.17, 0.26, and 0.20, respectively. There were high genetic correlations between BW42 with the weight and percentage of carcass components (from 0.65 to 0.98). Body weight at 42 d of age also showed positive genetic correlations with skin weight and SP (0.80 and 0.23, respectively), abdominal fat weight and AFP (0.44 and 0.21, respectively), and IFP (0.28). A positive genetic correlation between SP and AFP (0.51) was observed. Present results indicated that the percentage of breast intramuscular fat is a heritable trait and selection for increasing BW and decreasing abdominal and subcutaneous fats will improve carcass composition and breast meat quality in Japanese quail. In addition, selection against abdominal and subcutaneous fat does not change intramuscular fat and the quality of breast meat.

To study growth performance and meat quality traits (cholesterol content and intramuscular collagen properties) of quail, 3 trials were carried out. Trial 1 used males of generation 19 of the egg type Japanese quail (Coturnix japonica) selected previously (until generation 17) for low (n = 8) or high (n = 7) yolk cholesterol content as well as an unselected control (n = 11). Trial 2 used males of meat Pharaoh quail selected earlier (generations 1 to 6 and 9 to 11) on the basis of BW decrease after periodic deprivation of food (high decrease of weight, n = 10; low decrease of weight, n = 8) and unselected control (n = 10). Trial 3 compared males of English White quail, Manchurian Golden quail, and British Range quail. The birds were raised to 35 d of age. Quail were fed ad libitum commercial diets according to age and had free access to water. At slaughter, all birds were individually weighed (after a fasting period of 12 h), stunned, and decapitated. After the refrigeration period (24 h at 4°C), the left pectoralis superficialis muscle was removed from the carcasses, weighed, vacuum packaged, and stored frozen (-40°C) for analyses of cholesterol and intramuscular collagen (IMC; collagen and crosslink concentration). In trial 1, divergent selection for yolk cholesterol content did not significantly influence pectoralis superficialis muscle weight and IMC crosslinking of Japanese quail, whereas it significantly reduced growth and IMC amount. In addition, it had greater effect on the amount of cholesterol in meat; in fact, the meat of quail with low yolk cholesterol content contained lower cholesterol (-36.6%) than that of birds with high yolk cholesterol content. In trial 2, divergent selection on the basis of Pharaoh quail BW decrease altered IMC crosslinking, leading to variability in meat tenderness of Pharaoh quail. In trial 3, English White quail were significantly heavier than the other breeds.

Feed costs substantially affect the efficiency of poultry operations, justifying genetic improvement of feed utilization by selection. The current research was conducted to estimate genetic variance for the 4-wk feed conversion ratio (FCR) and its genetic correlations with BW, BW gain (WG), feed intake (FI), and residual feed intake (RFI) in Japanese quail. The data analyzed originated from a line selected for low FCR for 3 generations. In each generation, 35 sires and 70 dams were used as parents for the next generation. Body weight and WG were recorded on a total of 1,226 individuals, whereas FCR, RFI, and FI were recorded on 505 family groups. The results showed that heritability estimates (±SE) of BW at 28 d of age and WG between 7 and 28 d of age were 0.22 ± 0.05 and 0.28 ± 0.06, respectively. For FI, FCR, and RFI, significant genetic variances were estimated. Genetic correlations of FCR between 7 and 28 d of age with WG and FI between 7 and 28 d of age were -0.45 ± 0.09 and 0.24 ± 0.08, respectively. This implies that a low FCR is genetically related to a high WG and low FI. The genetic correlation between FCR from 7 to 28 d of age and RFI from 7 to 28 d of age was 0.26 ± 0.08, indicating that the 2 alternative feed efficiency traits are genetically different traits, and that the correlated genetic response in one of them in response to selection on the other is likely to be only moderate. Genetic correlations of RFI from 7 to 28 d of age with WG and FI between 7 and 28 d of age were 0.08 ± 0.04 and 0.74 ± 0.11, respectively. This reflects the fact that RFI is phenotypically independent of WG, which tends to make the genetic correlation between RFI and WG low as well. In conclusion, all the traits analyzed displayed significant genetic variance, allowing their genetic improvement by selection, yet the alternative feed utilization traits, FCR and RFI, displayed different genetic characteristics.

The current study was conducted to investigate the effect of short-term selection in Japanese quail for 4-wk BW and estimate genetic parameters of BW, carcass traits, and egg weight. A selected line and control line were randomly selected from a base population. In each generation, 39 sires and 78 dams were used as parents for the next generation. Data were collected over 2 consecutive hatches for 4 generations, and 1,554 records from 151 sires and 285 dams were used to estimate the genetic parameters. The genetic improvement of 4-wk BW was 9.6, 8.8, and 8.2 g in generations 2, 3, and 4, respectively. There was a significant effect of sex, generation, and line (P < 0.001). There was a significant difference for BW and carcass weights but not for carcass percentage components between sexes (P < 0.01). Females showed higher figures than males. The realized heritability for 4-wk BW was 0.55, reflecting the accuracy of selection. However the estimated heritability by using pedigree information was 0.26 +/- 0.05. The genetic correlation among BW and carcass traits was relatively high (ranging from 0.85 to 0.91). Inbreeding caused a decline in the mean for all of the traits, but its effect was only significant for 4-wk BW and carcass weight (P < 0.05). Selection for 4-wk BW improved feed conversion ratio 0.16 units over the selection period. Results showed there was a strong genetic correlation between 4-wk BW and carcass traits that suggests that early 4-wk BW can be used as a selection criterion to improve carcass traits. Also, intense selection resulting in high rates of inbreeding might result in decreased response to selection due to inbreeding depression.

We investigated the effect of selection for 4-wk feed conversion ratio (FCR) on genetic improvement of FCR, BW, weight gain (WG), feed intake (FI), and residual FI (RFI) in Japanese quail. The F line was selected for reduced FCR and the C line was maintained as a randombred control. In each generation, 35 sires and 70 dams were used as parents for the next generation. Three generations of selection were performed. Realized heritability for FCR was calculated as the ratio of cumulative selection response to the cumulative selection differential, and additionally, genetic response was quantified as the difference between the means of selection and control lines. The results showed that realized heritability for FCR after 3 generations of selection was 0.67. The mean FCR in F line and C line in the last generation was 2.13 and 2.61, respectively. This is 18.4% cumulative genetic improvement, or 6.1% improvement per generation. In the last generation, the means of F and C lines were 193 and 166 g for BW at age 28 d (16.4% total increase, or 5.5% per generation), 184 and 158 g for WG (17.2% total higher gain and 5.7% per generation), 393 and 413 g for FI (4.9% total higher consumption and 1.6% per generation), and -24.5 and 10.2 for RFI (-34.7 g of cumulative gain; -11.6 g per generation), respectively. These results show that selection to decrease FCR increases BW and WG and decreases FI and RFI as a correlated response.

Runway tests are considered indicative of underlying sociality in birds and their ability to make social discriminations and establish interactions among conspecifics. Herein, social reinstatement behavior in male juvenile Japanese quail selected for a reduced (LS, low stress) or exaggerated (HS, high stress) adrenocortical response to brief mechanical restraint was evaluated. Individual males were given the choice to reinstate with either 2 (low density, LD) or 8 (high density, HD) unfamiliar randombred conspecifics placed in goal boxes at opposite ends of a two-choice runway (TCRW). Then, the same males were individually retested in a single goal box runway wherein they were exposed to a goal box containing either a LD or a HD of males. In the TCRW, a higher (P < 0.01) number of HS males started their ambulation toward the goal box containing the HD as opposed to LD of conspecifics. The HS males also spent more (P < 0.01) time in close proximity (within a 10-cm close zone; CZ) to the HD (218 s) rather than LD (57 s) of conspecifics. In contrast, the LS males did not differ in their initial direction of travel and they spent similar average amounts of times in the CZ of their stimulus LD (141 s) and HD (124 s) conspecifics. Similar to the TCRW results, in the single goal box runway, HS males spent more (P < 0.01) time in the CZ of HD rather than LD conspecifics, whereas LS quail spent similar amounts of time in the CZ of LD and HD males. Considering that runways are novel (and therefore frightening) environments, our findings suggest that HS quail may find better shelter (i.e., more comfort) in close proximity to a larger rather than smaller group of conspecifics, whereas LS birds find groups of varying conspecific density equally attractive. The results suggest that LS quail possess favorable social adaptive qualities because they appear to be better suited to cope with situations where the density of conspecifics is variable.

Avian blastodermal cells at stage X are used to produce interspecies chimeras for heterogenous poultry reproduction. However, recipient-derived inner perivitelline layer (IPVL)-enclosed donor-derived ova may affect the efficiency of germline transmission via chimera. Among the proteins in the IPVL, zona pellucida protein C (ZPC) plays an important role in sperm-egg binding and inducing the acrosome reaction. In the present study, Peking duck blastodermal cells at stage X were transferred into subgerminal cavities of Japanese quail embryos at the same stage. Fourteen female duck-quail chimeras (duails) were hatched and raised to sexual maturity. After being screened by PCR, 3 duails were selected for examination of donor-derived ZPC. A total of 152 IPVL protein samples from the individual eggs laid by the 3 duails then underwent a preliminary examination for the presence of donor-derived ZPC by means of SDS-PAGE, periodic acid-Schiff staining, and Western blotting. A novel 35-kDa ZPC, not observed in quail but in duck, was found in the IPVL of the duails. Further analysis of peptide mass fingerprinting of Peking duck ZPC, Japanese quail ZPC, and the 35-kDa duail ZPC by matrix-assisted laser desorption-ionization reflectron time-of-flight mass spectrometry revealed that the novel ZPC was an isoform of quail ZPC. Moreover, comparison of N-terminal amino acid sequences of these 3 ZPC confirmed that the 35-kDa quail ZPC had more amino acids at the N terminus than did native quail ZPC, and none of the donor-derived ZPC was found in the duails. These findings suggest that it would be difficult to obtain donor-derived offspring by natural mating of interspecies chimeras.

Differences in developmental instability were assessed in female offspring of Japanese quail hens selected for reduced (low stress, LS) or exaggerated (high stress, HS) plasma corticosterone (B) response to stress and treated with a placebo or B during egg formation. Hens of each line were implanted (s.c.) with either a silastic tube containing no B (controls) or one filled with B. Female chicks hatched from each of the 4 line x implant treatment combinations were retained for examination of 3 bilateral traits at 130 d of age: length of the tibiotarsus, middle toe length, and distance between the auditory canal and the nares (face length, FL). Greater bilateral trait size variances were associated with measurement of tibiotarsus length (P < 0.04) and middle toe length (P < 0.06) in the HS line, supporting our previous findings in the opposite sex that developmental instability (i.e., fluctuating asymmetry, FA) of certain morphological traits is more pronounced in HS than LS adult quail. The HS quail are also known to exhibit greater adrenocortical responsiveness to a wide range of stressors, and they are more easily frightened than LS birds. Therefore, the line differences in FA (HS > LS) found previously in males and herein in females may simply reflect the differential responsiveness of the birds to chronic social and physical environmental stressors. In addition, the present study detected more (albeit marginally so, P < 0.06) bilateral variability (i.e., heightened FA) in FL of quail hatched from mothers treated with B, a finding entirely due to the very high FL variance observed in the female offspring of B-treated HS hens. Because others have found in ovo B treatment to be associated with heightened FA in chick tarsus bone length and because we have also demonstrated that greater yolk B deposition occurs in eggs from both unstressed and stressed HS quail hens than their LS counterparts, the present maternal B treatment may be acting independently, or in combination with HS genomic effects, to adversely affect developmental stability.

Increased fearfulness has been associated with adrenocortical activation. Maternal corticosterone (B) treatment increases egg B, and elevated B in ovo enhances chick avoidance of humans. Quail selected for exaggerated (high stress, HS) rather than reduced (low stress, LS) plasma B response to stress are more fearful, and more B is found in HS hen eggs. Thus, we used tonic immobility (TI) and hole-in-the-wall box (HWB) emergence tests to assess fear in chicks hatched from eggs of LS and HS hens implanted with B or no B (CON). The number of inductions required to attain TI, latency to first alert head movement, and duration of TI were determined in one study and the latency until first vocalization (LATVOC), numbers of vocalizations (VOCS), proportions of chicks vocalizing, and the latencies to head (HE) and full-body (FE) emergence from a HWB were assessed in another. The LS chicks required less inductions (P < 0.0005) and had shorter latency to first alert head movement (P < 0.02) than HS chicks, although the duration of TI was unaffected by any of the treatments. During the acclimation period of the HWB tests, more (proportions of chicks vocalizing; P < 0.0001) HS chicks alarm-called sooner (LATVOC; P < 0.0001) and more often (VOCS; P < 0.0001) than did LS chicks, and, although maternal implant treatment did not affect LATVOC, progeny of B-implanted hens showed a tendency toward less (P < 0.07) VOCS than the CON. Chicks hatched from eggs of B-implant mothers also took longer to achieve HE (P < 0.06) and FE (P < 0.05) from the HWB than did their CON counterparts. Stress line, implantation treatment, and their interaction did not alter HE or FE responses. The data suggest that quail stress line genome may or may not be affecting certain fear and alarm responses in chicks via the same mechanism(s) that underlies how elevating maternal B increases egg levels of B that in turn alters the fear behavior of progeny.

It has been found that GPR39 is an orphan receptor that belongs to the family of G protein-coupled receptors. In mammals, GPR39 has been shown to be involved in the regulation of gastrointestinal and metabolic function. In this study, we performed cDNA cloning for GPR39 in Japanese quail and characterized the tissue expression profiles of its mRNA. The cDNA encoded 462 amino acids, showing very high sequence homology to chicken GPR39 (95.5%) and moderate homology to mouse (64.7%), rat (63.7%), and human (59.9%) GPR39. Real-time PCR analysis revealed that GPR39 mRNA is expressed at high levels in the digestive tissues such as stomach, duodenum, jejunum, ileum, cecum, and colon and rectum and at moderate levels in the oviduct including infundibulum, magnum, isthmus, and uterus. These findings suggest that GPR39 may be involved in gastrointestinal and oviductal functions in Japanese quail.

Wild-type Japanese quail were compared with full-sibs with a yellow plumage color determined by an autosomal dominant mutation (Y), which is lethal when homozygous. These quail have wheat-straw yellow-colored feathers. Early growth was slower in yellow quail that had 2.4% lower BW than wild-type quail (149.3 g vs. 153.0 g) at 28 d of age. The BW, however, was similar for yellow and wild-type males at 35 d, and it remained so throughout the last part of the growth of the quail monitored until the age of 120 d, as indicated by the very close parameters of the monomolecular growth curve [BW= A - B exp(-kt)] obtained for the 2 groups. Yellow plumage color was also associated with a more difficult adaptation to housing (measured by temporary BW loss) in individual cages and to a significantly 0.2 degrees C lower body temperature at 42 d, but feed consumption and residual feed intake were similar for the 2 plumage color phenotypes. Breast and liver weights were similar in the 2 groups, but abdominal fat was 24% higher (4.66 vs. 3.76 g) in yellow quail. There is some association between the correlated effects of the Y gene in quail and those of the lethal mutation A(y) at the agouti locus in the mouse.

The levels of mRNA expression in regulatory genes that are involved in the pathological changes of aortic atherosclerotic and fibroblastic intimal thickening was investigated in Japanese quail. The quail were divided into a control diet group and an atherogenic diet group. The quail were euthanized at 2, 4, 8, and 12 wk after consuming either a control diet or an atherogenic diet. Thereafter, both histological and immunohistochemical studies and mRNA expression analysis of the cell-cycle-regulating genes in aortic atherosclerotic lesions were performed on selected ascending aortas and their large branches. In the atherogenic diet group, aortic lipid-containing intimal and atheromatous lesions were seen mainly at 8 and 12 wk, respectively. Semiquantitative reverse-transcription PCR was used to analyze the alterations of mRNA expression on the development of atherosclerotic lesions. Messenger RNA expression of the c-fos and c-src genes showed peak levels at 8 wk in the atherogenic diet group. However, no significant alteration of c-jun mRNA expression was noted during the entire experimental period. According to the progression of aortic atherosclerotic lesions, c-myc mRNA expression in the atherogenic diet group increased chronologically, and the highest level was observed at 12 wk. Alterations in mRNA expression of proliferating cell nuclear antigen and the p27 gene were similar to that of c-myc. The levels of c-myc, proliferating cell nuclear antigen, and p27 mRNA expression was significantly correlated with the degree of aortic atherosclerotic lesion development at 12 wk in our experiment.

A strain of Japanese quail with the polyuria disorder (excessive urination) was developed from founders that regurgitated water spontaneously. A back-cross with a nonpolyuric quail line showed that the polyuric strain was fixed for an autosomal recessive mutation that also induced polydipsia (excessive drinking). Plasma levels and brain mRNA contents for avian Arg vasotocin were little affected by the mutation, but plasma avian Arg vasotocin was 13-fold higher and brain mRNA contents were significantly increased in both normal and mutant quail following a 24-h water deprivation. Affected and normal birds had similar performance traits (egg production and quality, feed intake, and gross carcass traits), but residual feed consumption was higher in polydipsic males. These results are consistent with the hypothesis that this strain was fixed for a mutation similar to the di gene described in the chicken and which induces nephrogenic diabetes insipidus. This new strain of Japanese quail might constitute a convenient model for the analysis of the underlying mechanisms of the disorder in birds and for comparative study with mammals.

Corticosterone is linked to testicular depression, and in Coturnix, a relatively photorefractory species, day length and androgen dependency in cloacal gland development and foam production are evident. Furthermore, male quail selected for reduced (low stress, LS) rather than exaggerated (high stress, HS) plasma corticosterone stress response show more photo-induced reproductive development, greater resistance to reproductive declines induced by exposure to very short days, and a quicker recovery to a higher reproductive level upon return to long days. To determine whether a milder reduction in day length would also influence stress line reproductive photoresponsiveness, and perhaps photorefractoriness, males grown on 16 h of light were given 13 h of light for 4 wk followed by a return to long days for 12 wk. Cloacal gland measurements were made following the initial stimulatory photoperiod and weekly thereafter during the 2 light treatments. Plasma testosterone was determined initially, after 4 wk of light reduction, and at the end of the study, along with BW, testes weight (TWT), and TWT relative to BW. Cloacal gland volume (CVOL) was greater in LS than HS males grown on long days. Whereas exposure to 13 h of light reduced CVOL in both lines, line differences (LS > HS) persisted during the first 3 wk of light reduction. Moreover, by 2 wk of rephotostimulation, and weekly thereafter, line differences (LS > HS) in CVOL reemerged. Cloacal gland foam production and the proportion of individuals that produced cloacal gland foam responses reflected changes in CVOL. The BW did not differ by line, yet LS males had a higher TWT and TWT relative to BW than HS ones. All individuals, however, exhibited relative photorefractory responses. Whereas none of the LS males completely resisted reproductive regression induced by a 3 h light reduction, LS males showed other reproductive benefits upon mild photocastration and subsequent rephotostimulation (e.g., greater resistance to CVOL and cloacal gland foam production losses during a mild light crash and quicker restoration to full reproductive potential upon relighting).

Fully pedigreed records of a Japanese quail population were analyzed for genetic parameters of egg and BW traits. A restricted maximum likelihood (REML) procedure was applied in univariate and bivariate analyses. Quantitative genetic analyses, including maternal effects, were carried out on the records of 947 male and 861 female birds (total = 1,808). The traits were analyzed with bird as a random factor to fit the additive direct effect, bird being the individual for which the trait was recorded, namely hen (dam) for egg traits and chick (progeny) for BW. Permanent environmental effects (0.29 to 0.35) on egg traits were higher than corresponding heritabilities (0.18 to 0.25). Significant maternal genetic and maternal permanent effects were measured for hatching BW. The heritabilities of weekly BW were low, and decreasing by 5 to 6 wk of age. They were 0.07, 0.18, 0.19, 0.18, 0.19, 0.13, and 0.15 from hatching to 6 wk, respectively. Strong correlations were detected between direct genetic effects for egg traits and maternal genetic effect for BW traits. Applying such detailed analyses in the study of both egg and BW traits provides procedures to specifically evaluate Japanese quail and poultry in general. The results illustrated that the maternal permanent environmental effects made larger contributions to the variability of egg traits than did direct genetic effects. This situation implies that rearing of birds, healthcare, and feeding are very important determinants of egg characteristics.

The influences of age (4 to 12 wk), sexual maturity status, and sex on hypothalamic-pituitary-adrenal (HPA) axis responsiveness were investigated by measuring changes in peripheral basal levels of corticosterone (B) and responses to 10 min of physical restraint in a crush cage or injection of 1-24 adrenocorticotropic hormone (ACTH) in 2 genotypes of Japanese quail divergently selected for long (LTI) or short (STI) duration of tonic immobility (TI). Although gonad development was more advanced in male STI quail, most birds were still immature at 4 wk of age, but sexual maturity was fully acquired by 6 wk of age in both sexes and genotypes. This change was associated with increases in basal B levels in both genotypes and sexes. On the other hand, HPA axis responsiveness to restraint and adrenal responsiveness to 1-24 ACTH injection remained stable in STI quail, whatever the age. Conversely, significant responses to restraint compared with basal B levels were only observed at 4 and 6 wk of age, and adrenal responsiveness increased with age in LTI quail. Moreover, higher B levels were measured in response to restraint in STI than in LTI quail, whereas similar adrenal responses were measured at 9 and 12 wk of age. We concluded that an increase in basal B levels is associated with the stage of sexual maturity acquired, but it did not affect HPA axis responsiveness or adrenal B response capacity. On the other hand, age affected HPA axis responsiveness and adrenal B response capacity in LTI quail of both sexes but not in STI quail. It is hypothesized that functional HPA axis maturity occurs after 6 wk of age in the LTI genotype, but it is reached by 4 wk of age in the STI genotype. In conclusion, the divergent selection program for TI conducted on quail resulted in changes in HPA responsiveness that probably resulted from differences in development rate and function of the adrenal glands or other upstream structures of the HPA axis.

The aims of this study were to investigate the existence of a circadian rhythm of basal corticosterone (B) plasma concentrations in male and female Japanese quail lines divergently selected for long (LTI) or short (STI) duration of tonic immobility (TI) and the possible effects of photoperiod length on corticotropic axis reactivity. Significant peaks in B levels were observed throughout the day in 3 out of the 4 groups used in our experiments. However, B levels remained very low for all groups (< 5.0 ng/mL) and there was no consensus between groups. We therefore have no evidence from our results that basal B levels follow a circadian rhythm in adult STI and LTI quail held under a long photoperiod (16L:8D). We also showed that rearing under a long photoperiod (16L:8D) was associated with higher basal B levels and higher B adrenal response capacity to 1-24 adrenocorticotropic hormone (ACTH) injection in the STI and LTI lines compared with a shorter period (8L:16D). Higher hypothalamic-pituitary-adrenal (HPA) axis responsiveness to restraint in a crush cage was also measured in female quail reared under the long photoperiod, and similar responses were measured under both photoperiods in males. This result suggests that the effects of photoperiod length involve both local and more central mechanisms in the control of HPA axis responsiveness according to sex. On the other hand, we showed that the genetic selection program for TI responses induced greater increases in the B level following restraint in STI quail than in LTI quail of both sexes under both photoperiods, but the B adrenal response capacity was similar for both lines and sexes. Although further investigations on both lines regarding adrenal sensitivity are necessary before being able to conclude definitively, our findings strongly suggest that the differences observed in HPA axis responsiveness to restraint between lines are probably not due to differences in adrenal function itself but may involve upstream structures of the HPA axis.

Decades of divergent selection for 4-wk BW has produced 3 lines of growth-selected Japanese quail. P line quail have been selected for >110 generations for 4-wk posthatch BW and are nearly 3-fold larger than the randomly bred control C line. The H line has been selected for high 4-wk BW for 52 generations and the L line has been selected for low 4-wk BW for 54 generations. To identify differentially expressed genes that may play a role in defining the differences in these lines, a DNA array containing 4,704 random anonymous cDNA clones from 8-d C line embryos was screened using isotopically-labeled cDNA from the different quail lines. Array analysis yielded 3 differentially expressed cDNA clones that were confirmed by Northern blot analysis. The 35-kD quail EB1 protein, previously unidentified, was shown to have elevated transcripts in the L line and decreased transcripts in the H and P lines, compared with the C line. It was also widely expressed in embryonic and adult tissues by BLASTN analysis of chicken expressed sequence tag (EST) libraries. Two other cDNA clones are novel sequences expressed at higher levels in the L line and at lower levels in the H and P lines, one of which was more selectively expressed in embryos and adult tissues by BLASTN analysis. These limited findings suggest that anonymous cDNA array analysis is a productive means to identify differentially expressed genes in growth-selected poultry.